Chapter 3. How SSL VPNs Work

As described in Chapter 1, SSL VPN products allow users to establish secure remote-access sessions from virtually any Internet-connected web browser. Delivering the ability for people to access e-mail, critical information systems, files, and other network resources from virtually anywhere is not a trivial task. Despite often appearing to onlookers as simple devices, SSL VPNs employ complex and advanced technology.

At present, there are no official standards for SSL VPN technology (other than for SSL, HTTP, and other SSL VPN subcomponents). The few third-party SSL VPN 'certifiers' that exist, primarily examine features, not the internal mechanisms of delivering those features. With a highly competitive climate currently present in the SSL VPN market, vendors are also reluctant to disclose the details of the inner workings of their products. Yet, even without official information from each vendor, it is possible to understand SSL VPN technology. Every offering...